This is absolutely fake and scam. This scam giveaway I have been seeing for many days! I don't know what is your intention, because this is your first post in the forum, maybe you are trying to convince people in a different way to invest in this scam, then I must say you are in the wrong place. Don't try to scam people's money in this rough time, these scammers should not stay in this world, they don't deserve it.
This kind of action are absolutely scam because if you are just giving a number of one dollar and now you will get a two dollar profit I think they are just supporting the small amount of value on the first places so the users may encourage to make an investment on their platform looks like the OP did and they pay back your money immediately also they are a lot of fall on this scam and I think this thread may remove to the Scam Accusations because no-one will believe on this kind of action also I will not encourage most of the newbies to visit the platform this is just like Ponzi scheme. I highly recommended making a research before you entering this kind of scamming platforms.
If it's to be good to be true then it's probably not true. I've encountered tons of doublers like that when i first entered the Bitcoin space. I was noob back then and started to invest in HYIP, Doubler and Cloud mining so i can tell those types of things are scams meant to bait you. Because nothing in this world can double your money in a matter of seconds except for trading.
Most of the doubler coins are scam because how can you make a money if you are just trying to double the funds of others it is just a big loss on your side if you are a developer.